Background: The primary risk factors for osteoarthritis at the knee joint are old age, obesity and sex where females have higher probabilities to have osteoarthritis of knee than men. The secondary risk factors are internal derangements such as meniscal or ligament tear caused due to trauma to knee joint, almost 50% of people with meniscus or anterior cruciate ligament tear develop osteoarthritis at the knee joint. Joint mal-alignment is known to be an etiological factor for occurrence and development of knee osteoarthritis, due to increase in joint stress.
Objectives: To study and compare lower extremity joint kinematics of the affected limb in patients with unilateral knee osteoarthritis during SOS, SBS and SW locomotion patterns.
Materials and methods: Fifteen patients participated in this study. The stair ascent and descent were performed by patients using 5 stair locomotion patterns i.e. step over step (SOS) pattern, step by step pattern leading with affected extremity (SBSA1), step by step pattern leading with non-affected extremity (SBSNA1), sideways stair pattern leading with extremity (SWA1) and sideways stair pattern leading with non-affected extremity (SWNA1).Kinematic data was collected using Noraxon motion analyser (3D Inertial Sensor System USA).
Results: On kinematic comparison of the different types of stair ascent locomotion patterns, the observed trend of the highest to the least movements at the affected knee joint was: SWascA1 (72.6 ±15.2) > SBSascA1 (69.5 ±13.6) > SOS ascent (63.7 ±11.8) > SBSascNA1 (42.1 ± 10.8) > SWascNA1 (32.8 ±8.7). During stair descent, the observed trend was: SBSdscNA1 (68.2 ±9.2) > SOS descent (68.1 ±10.4) > SWdscNA1 (61.8 ±12) > SBSdscA1 (35.1 ±8.5) > SWdscA1 (27.3 ±4.8).
Conclusion: All three types of stair locomotion patterns i.e. SOS, SBS & SW locomotion differ kinematically from each other with respect to certain joint angles. Based on the results, the preferred patterns for stair ascent could be SWascNA1 and SBSascNA, and for stair descent could be SWdscA1 and SBSdscA1, due to lower kinematic demands at the knee joint.
Key words: Osteoarthritis, SOS, SBS, SW patterns of stair locomotion.
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